Casing perforating gun



F. l. ALEXANDER CASING PERFORATING vGUN July 22, 1941.

Filed NOV. 3, 1959 v Patented July z2, 1941 s PATENT OFFICE cAsINGPERFORMING GUN Ford I. Alexander, Whittier, Calif.

-Application November 3, 1939, Serial No. 302,681

19 Claims.

'I'his invention relates generally to perforating guns for well casingand more particularly to improvements in the shooting barrel andexplosive chamber in casing perforating guns. 'I'he present inventionmay be considered as dealing in most of its aspects with improvements inthat type of casing perforating gun in which there is provided a numberof chamber blocks, usually at III. This gun body is formed in its sidewith a plurality (but one being illustrated in Fig. 1) of verticallyspaced horizontal bores or sockets II, each met by a reduced counterboreI2 extending inwardly from the opposite side of theV gun body, the twobores being joined by an annular shoulder I3 which is here shown asbeveled or conical. The forward end of bore II is screwthreaded, as

indicated at I4.

of barrel form, mounted in lateral sockets or recesses in an elongatedgun body, each such block or barrel containing or housing an explosionchamber and a shooting bore.1

A general object of the invention may be stated to be the provision ofan improved barrel oi' substantially increased strength and durability.

A further object of the invention is to provide a barrel constructionhaving an explosion chamber so designed that increased iiring power isdeveloped. Y

.A further object of the invention is to provide a form of barrel havinga shooting bore of maximum length. l

A still further object of the invention is the provision of a barrel inwhich access to the explosion chamber is readily gained and in whichsuch access is not rendered more dimcult by repeated firing.

A still further object of the invention is to provide improved means forsealing the explosion chamber against external liquid pressure.

It is also an object of the invention to provide a novel means formounting the gun barrel within the elongated gun body, vthe mountingbeing such as to relieve the usual threaded connection between barreland body of stress and strain during firing of the gun.

Further objects, features and advantages of my invention will appear inthe course of the following detailed description of a present preferredembodiment thereof, reference for this purpose being had to theaccompanying drawing in which:

Fig. 1 shows a portion of a gun body, with parts broken away to show thegun barrel of the present ,d invention in longitudinal vertical section;

Fig. 2 is an enlarged detail taken from Fig. 1;

Fig. 3 is a detail of a sealing cup;

Fig. 4 is a detail taken as indicated by line 4-4 of Fig. 1; and

Fig. 5 is a modication showing a cartridge adapted for use within thebarrel of the present invention.

A portion ofthe elongated gun body, preferably cylindrical in externalform, is designated 'I'he block or barrel, designated generally bynumeral I5, has a preferably: cylindrical body portion I6 of such adiameter as to slide freely within bore lI, the body being formed at itsforward end with screwthreads II adapted to cooperate with threads I4,and with a hexagonal projection I8 by which it may be engaged with awrench for `thepurpose of screwing it in or out of the gun body. 'Iherearward end portion I9 of the barrel is reduced to such a diameter aswill be received freely within reduced body bore I2, and the gunv isformed with a beveled shoulder 20 adapted to seat against the aforementioned beveled body shoulder I3. Screwthreads I4 and I'I are designedto be suflicientlyloose fitting that no substantial strain is placedthereon when the gun is fired, the reaction being received principallyby body shoulder I3.

'Ihe barrel I5 is of'comparatively large diameter, and is thereforerelatively heavy. This is of advantage not only in providing a largeamount of stockaround the shooting bore, there-4 by reducing oreliminating the common tendency of the barrel to crack or split, but'also reduces the kick-back of the barrel against the elongated gun bodyI0. The loose threaded connection between the barrel and the gun bodyserves to position the barrel against body shoulder I3, and while themajority. of the reactiondue to the explosion is absorbed,w by reason ofthe comparatively large mass of the barrel, what kickback does occur isborne principally by shoulder I3. As stated, however, the larger shareof the reaction due to the explosion is absorbed by/ reason of the largemass of the barrel. and the gun body may therefore be relatively light,serving principally simply as a carrier for the barrels.

The drawing shows a construction suitable for a gun designed forrelatively small diameter casing. With larger casing, the diameter ofbody I0 and the length of barrel I5 can of course be increased, theincrease in barrel length being preferably in the portion in which theshooting bore is contained, so as to provide a shooting bore of maximumpossible length, it being of course understood that the longer theshooting bore, the greater is the ilring power of the gun.

On the other hand, since, as pointed out above,

from hanging up on the casing during Vertical travel therein.

Barrel I5 is provided with an axial shooting bore 25,-within which ispositioned the usual projectile 26. 'Ihis bore is preferably formeddirectly in the stock constituting the barrel I5,y

rather than in a small insert barrel, .as in a common type of priorpractice, this preferred construction being of such increased strengththat barrel splitting is entirely eliminated. An enlarged counterbore 21is drilled inwardly from the outer end of the barrel, forming an annularseating shoulder 28. A flexible cup 29, preferably oi' soft rubber, isseated on shoulder 28, its sides fitting snugly within counterbore 21,and a frangible disk 30 of a diameter somewhat larger than that ofshooting bore 25 is pressed inside the cup and seated against the bottomthereof, the bottom being supported by shoulder 28.

The lip or side of the cup is tapered, as indicated at 29', so that thepressure of the external liquid will press the side walls of the cupinto tight sealing engagement with the surface of counterbore 21. Thepressure fluid also acts against disk 30, pressing the latter tightlyagainst the bottom of the cup and thus pressing the cup into tightsealing engagement with seatingv shoulder 28. 'I'he higher the externalliquid pressure, the tighter is the tapered edge or lip of the cuppressed against surface 21, and therefore the tighter is the liquidseal. It will be understood that the frangible disk 30, while ofsuflicient strength to withstand the external liquid pressure, is easilypunctured by the projectile 28 when the gun is fired.

Extending inwardly into the rearward end of barrel I5, in coaxialrelationship with shooting bore 25, is a screw'threaded socket 35adapted to receive a screwthreaded breech plug 36, while extendinginwardly from the inner end of socket 35 is an explosion chamber bore31, of a diameter somewhat less than that of socket 35, yet greater thanthat of shooting bore 25, the inner end of bore 31 meeting bore 25. Anannular seating vshoulder 38 is formed at the juncture of socket` 35with explosion chamber bore 31, while a conical seating surface orshoulder 39 is formed at the juncture of explosion chamber bore 31 withshooting bore 25. External leakage pressure which might otherwise leakto the explosion chamber around plug 36 is sealed off by a sealingwasher 40, preferably of lead, seated against shoulder 38 and tightlyengaged by the inner end of breech plug 36. A conical sealing disk 42,complementary to conical seating surface 39, is seated on the latter,and is preferably attached to the rearward end of projectile 26, as byspot welding.

'Ihe powder charge is preferably in the form of a compressed powderpellet 45 placed inside chamber 31 immediately to the rear of disk 42.To the rear of this powder pellet 45 I preferably place a soft metalexpansive cup 46, formed of sharp edge 46a, for a purpose which willappear later.

The inner end of breech plug 36 is formed with a socket or recess 50 foran electrically fired fuse 5I, the fuse being provided with anelectrical conductor 52 which extends outwardly through` plug 36 via acentral duct 53 leading from the bottom of recess 5| through the outerend of the plug. Fuse 5I may be of a type grounded to the plug 36 inwhich it is seated. This fuse is preferably of a match-head type, suchas manufactured by the Atlas Powder Co., and projects a flame from itsforward end when 'heated by pas'- sage' of an electrical current. Suchfuses are known and will require no detailed description herein.

The outer or rearward end of breech plug 36 is formed with a hexagonalprojection 55 adapted for convenient engagement by a wrench, and thisprojection 55 has an annular recess 56 formed coaxially with duct 53,said recess being adapted to receive any suitable packing means for thefuse conductor, one preferred form of which is illustrated in thedrawing at 51. Hexagonal projection 55 is provided with a number ofnotches 58 adapted to receive the fuse conductor 52. After the breechplug has been screwed home, the fuse conductor 52 is placed in the notch58 closest to the extremity of an electrical conductor 59, the latterbeing arranged on the gun in any appropriate manner. Electricalconnection is made between conductors 52 and 69, as at 60. It will beunderstood that the conductor 59 is part of a cable leading from theelectrical control or firing system, not shown, and that any arrangementof such cable and its separate conductors on or within the gun body maybe employed as desired. I here show a cable 62 positioned within arecess or groove 63 extending downwardly along the side of the gun body,the conductor 59 being led oft via an angular passageway 64 to a pointjust above the breech plug 36, the connection between conductor 59 andfuse wire 52 being made as previously explained.

The preferred fuse wire sealing means illustrated at 51 (see Fig. 2)comprises a flexible cup 66, preferably of rubber, seated within recess56 and formed with a central mound 61 having a central aperture 68adapted to lit snugly about fuse wire 52. A disk 68 having a centralaperture 69 adapted to pass a conductor 52 is seated inside cup 66, andcompresses mound 61 tightly about wire 52, thereby forming apressure-tight seal.

It will be seen that the cup member 46 is positioned between fuse 5I andpowder charge 45. 'I'he base of this cup member is formed with a smallcentral aperture 10, adapted to pass the re from the fuse when the fuseis set off. Thus, when the conductor 59 is connected-through a batteryto a ground on the gun body, the fuse 5I is fired, the flame passingthrough aperture 10 and igniting powder charge 45. The small aperture 10confines the flame to a small diameter jet, the flame thus being moreconcentrated and more forcefully directed than if the confining aperture16 were not employed, with the result that '2,250,056' powder charge 45is, ignited lwith increased rapidity.. The normal llame from a fuse ofthe type illustrated results fin la comparatively slow burning o1' thepowder'charge; the jetted flame from the aperture 10, on the other hand,heats the powder charge much more rapidly andresults in a much morerapid explosion of the charge, thus buildingup very high explosivepres-l sure within the explosion chamber'before the its maximum beforethe projectile leaves the gun.

The result is, of course, to impart to the projectile very greatlyincreased muzzle velocity.

As the explosive pressure is built up, the disk 42 is seated tightly, bythis pressure, on the conical seat 39, thus sealing against loss ofpressure until the pressure is suiiicient to rupture the disk 42. Theconical disk 42 pressed against seat 39 acts as a valve, sealing tightlyagainst loss of pressure. 'I'hese described provisions result in theexplosive pressure being built up to substantially increased valuesbefore the disk 42 is ruptured and the projectile is discharged, withthe result that much increased firing power is developed. i

'I'he explosion within chamber 37 results in expanding the' taperedsides of cup 46, thus pressing the sides of said cup into tight,pressure-sealing engagement with the walls of the explosion chamber, sothat little back pressure escapes around the sides of said cup. Thebreech plug is suiiiciently small in diameter that the total back forcetransmitted through cup 46 to the inner end of the breech plug when thegun is ilred is not sufficient to place any undue strain on the breechplug threads. This is a feature of importance, since the avoidance ofstrain on the breech plug threads means that the threads will not becomebound or deformed even after extensive service, and the plug maytherefore always be easily and readily unscrewed. Attention is directedto the preferred use of powder charge in the form of a compressed powderpellet. Such a powder pellet occupies a much smaller space than a chargeof loose powder, and the powder chamber may thus be of reduced size,which means increased explosive pressure when the charge is set olf.

Fig. 5 shows a modication, in which the projectile, conical sealingdisk, powde charge, expansive cup and fuse are made up as an integratedcartridge. In the illustrative form of Fig. 5, the sea-ling disk 42a. towhich is attached projectile 26a, is formed as a part of a shell 80encasing the powder charge 45a and expansive cup 46a. being crimpedabout the expansive cup as at 8|. The fuse 82 is seated within the cup,as at 83, and has a fuse wire 84 extending through the base of the cup.The wire 84 is of course insulated from the cup, while the fuse iselectrically grounded to the cup, and therefore, through shell 80, tothe barrel I5 and the gun body. This cartridge as thus described isplaced y within the barrel I5 of Fig. 1, the sealing washer 40 inserted,and the breech plug 36 screwed home.

Of course, the' fuse socket 50 in the end of the breech plug may in thiscase be eliminated.

The gun construction afforded by the present invention enables use of abarrel of relatively large size, in both/ diameter and length, for a gunbody of a given diameter.

ItV will be understood the drawing and description are merelyillustrative c? one practical form of the invention, and that variouschanges in design, structure and arrangement may be made withoutdeparting from the spirit and scope of p the invention or of theappendedclaims.

I claim:

1. In a barrel adapted to be mounted on a casing perforating gun body,an yinternal s ocket in the rearward end of said barrel, a shooting borein said' barrel alined with said socket and cxtend` ing through theforward end of said barrel, and a breech plug mounted in said socket,there being an explosion chamber within said barrel between the innerend of said inner end of said shooting bore.

2. In a barrel receivable Within a lateral re cess in a casingperforating gun body, an internal screwthreaded socket in the rearwardend of the barrel, a breech plug screwthreaded within said socket, anexplosion chamber within said bar. rel forwardly of said breech p1ug,and a shooting A bore in said barrel extending from said explosionchamber ,through the forward end of the barrel.

3. A barrel for a casing perforating gun, comprising an externallyscrewthreaded barrel body, a screwthread socket in the rearward end ofsaid body, a reduced explosion chamber bore extending inwardly in thebarrel body from said socket, there being an annular seating surface atthe juncture of said socket and said explosionl chamber bore, a sealingwasher against said seating surface, a breech plug screwthreaded withinsaid socket and engaging said sealing washer, and a shooting bore, ofdiameter less than that of the explosion chamber bore, extending fromthe inner end of said explosion chamber bore through the forward end ofthe barrel body.

4. A barrel for a casing perforating gun, comprising a barrel bodyhaving a screwthread socket in its rearward end, a breech plugscrewthreaded within said socket, an explosion charnber bore extendinginwardly in said body from said socket, a shooting bore extending fromthe inner end of said explosion chamber bore through the forward end ofsaid barrel body, and an expansion cup disposed within the outer endportion of said explosion chamber bore, with its depression side facingtoward the shooting bore, the space within said explosion chamberforwardly of said cup being adapted to `contain an explosive charge, andthe sides of said eX- pansion cup being adapted to be pressed into'sealing engagement with the explosion chamber adapted to contain anexplosive charge, and the sides of said expansion cup being adapted tobe pressed into sealing engagement with the explosion chamber bore whenthe charge within the explosion chamber is fired.

6. In a casing perforating gun, a body having a socket formed therein, abreech plug removably mounted in said socket, an explosion chamber plugand the within said body extending inwardly of said breech plug, ashooting bore in said body extending from said explosion chamber, saidshooting bore being of less cross-sectional area than the explosionchamber, and there being a conical seating surface formed at thejuncture of said shooting bore with said explosion chambenand acomplementary conical frangible disk seated on said conical seatingsurface.

7. In a perforating gun, a body having a shooting bore therein, anenlarged counterbore at the forward end of said shooting bore, ailexible sealing cup seated within said counterbore, and a pressureholding disk seated within said cup.

8. In a casing perforating gun, a body having an explosion chamber, ashooting bore extending from one end of said explosion chamber, meansfor positioning a fuse adjacent said chamber, and a wall between thefuse carried by said positioning means and the firing chamber having asmall fire-concentrating aperture opposite said fuse.

9. In a casing perforating gun, a `body having a screwthread socketformed therein, an expiosion chamber bore extending inwardly in saidbody from said socket, a shooting bore extending from the inner end ofsaid explosion chamber bore,A an expansion cup disposed within the outerend portion of said explosion chamber bore, with its depression sidefacing toward the shooting bore, the space within said explosion chamberforwardly of said cup being adapted to contain an explosive charge, asmall aperture in the base of said cup, a breech plug screwthreadedwithin said socket, the inner end of said plug being adapted to supportthe base of said expansive cup when the charge Within the explosionchamber is fired, and a fuse-receiving recess in the end of said breechplug opposite said aperture.

10. In a casing perforating gun, the combination of a gun body having atransverse socket extending entirely therethrough frcm one side to theother, a barrel mounted within said socket and extending substantiallyentirely through said gun body, a screwthread socket in the rearward endof the barrel, a breech plug screwthreaded within said-socket, anexplosion chamber within said barrel forwardly of said breech plug, anda shooting bore in said barrel extending from said explosion chamberthrough the forward end of the barrel 11. In a casing perforating gun,the combination of an elongated gun body having a transverse socketextending therethrough from one side to the other, a barrel receivedwithin said socket and extending substantially entirely through said gunbody, a rearwardly facing shoulder on said barrel and a cooperatingshoulder within said socket adapted to be engaged by said barrelshoulder, a screwthread socket in the rearward end of the barrel, abreech plug screwthreaded within said socket, an explosion chamberwithin said barrel forwardly of said breech plug, and a shooting bore insaid barrel extend- .ing from said explosion chamber through the forwardend of the barrel.

12. In a casing perforating gun, the combination of an elongated gunbody having a transverse socket extending therethrough from one side tothe other, a barrel received within said socket, a.

rearwardly facing shoulder on said barrel and a cooperating shoulderwithin said socket adapted to be engaged by said barrel shoulder,coacting loose fitting screwthreads on said barrel and inside saidsocket, a screwthread socket in the rearward end of the barrel, a breechplug screwthreaded within said socket, an explosion chamber within saidbarrel forwardly of said breech plug, and a shooting bore in said barrelextending from said explosion chamber through the forward end of thebarrel.

13. In a casing perforating gun, the combination of an elongated gunbody having a transverse socket, a barrel received within'said socket, arearwardly facing shoulder on said barrel and a cooperating shoulderwithin said socket adapted to be engaged by said barrel shoulder,coacting loose tting screwthreads on said barrel and inside said socket,a screwthread socket in the rearward end of the barrel, a breech plugscrewthreaded within said socket, an explosion chamber within saidbarrel forwardly of' said breech plug, and a shooting bore in saidbarrel extending from said explosion chamber through the forward end ofthe barrel.

14. In a barrel receivable within a lateral recess in a casingperforating gun body, an internal screwthreaded socket in the rearwardend of the barrel, a breech plug screwthreaded within said socket, anexplosion chamber within said barrel forwardly of said breech plug, anda shooting bore in 'said barrel, of lesser cross-sectional area thansaid explosion chamber, extending from said explosion chamber throughthe forward end of the barrel.

15. A relatively massive and thick-walled barrel for a casingperforating gun body, said barrel having an internal screwthreadedsocket in its rearward end, a breech plug screwthreaded within saidsocket, there being an explosion chamber within said barrel forwardly ofsaid breech plug socket, and a co-axial shoting bore in said barrel, oflesser cross-sectional area than said explosion chamber, extending fromsaid explosion chamber through the forward end of the barrel.

16. In a casing perforating gun, the combination of a gun body having atransverse socket extending entirely therethrough from one side to theother, a barrel mounted within said socket and extending substantiallyentirely through said gun body, a screwthreaded-socket in the rearwardend of the barrel, 'a breech plug screwthreaded within said socket, andbeing of sumciently small diameter to be removable from the end of thebarrel through the endv portion of the transverse socket in. the gunbody while the barrel is mounted in the gun body, an explosion chamberWithin said barrel forwardly of said breech plug, and a shooting bore insaid barrel extending from said explosion chamber through the forwardend of the barrel.

17. In combination in a perforating gun, a shooting bore, an enlargedcartridge chamber at the breech end of said shooting bore, a shoulderbetween sai-d bore and chamber, and a cartridge embodying a shear walladapted to be positioned adjacent said shoulder and to overlap thebreech end of the shooting bore all around, a cylindrical cartridge sidewall extending rearwardly from said shear wall, and a closure diskclosing the rearward end of said side wall, said cartridge' between saidbore and chamber, and a cartridge embodying a shear wall adapted to bepositioned adjacent said shoulder and to overlap the breech end of theshooting bore all around, a cylindrical cartridge side Wall integralwith and extending rearwardly from said shear Wall, and a closure diskclosing the rearward endv of said side wall, said cartridge beingadapted to contain an explosive charge, and said shear wall beingadapted to resist shearing over the area of said shooting bore until arelatively high explosive pressure has been built up inside thecartridge.

19. In combination in a perforating gun, a shooting bore, an enlargedcartridge chamber at the breech end of said shooting bore, a shoulder 15between vsaid bore and chamber, and a cartridge embodying a shear walladapted to be positioned adjacent said shoulder and to overlap thebreech end of the shooting bore all around, a projectile attached tosaid shear Wall at the center and

